Using wireless radio frequency transmissions provides great freedom to configure networks. Wireless models become more popular because inconvenience and expenses associated with physical connectivity, i.e., through wires, are eliminated. The wireless model is also generally more flexible in that the potential paths for communications are not constrained by any wired connection.
Limitations in the wireless communication model for networks include signal interference and power limitations, which both constrain data capacity. Signal interference is the natural interference inherent in wireless communications. Power limitations arise from communication standards, e.g., the Federal Communication Commission standards in the United States, that limit the power that transmitters may use for a transmission. Power limitations also arise from the portable power sources sometimes used by nodes in wireless networks.
Power and data rate constraints have been addressed on a node to node level, but an efficient and systematic method for accounting for these constraints on a network wide basis is believed lacking. Yet, even modest efforts at centralized scheduling in networks have made significant contributions to increase network capacity. In the conventional IEEE 802.11 standard there is a point coordinate function to centralize scheduling of users in a network. The HDR (1EX VDO) standard also schedules transmissions centrally on downlink channels. There remains a need, however, for a systematic approach that is effective and computationally feasible.